/*
 * TLSv1 Record Protocol
 * Copyright (c) 2006-2007, Jouni Malinen <j@w1.fi>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * Alternatively, this software may be distributed under the terms of BSD
 * license.
 *
 * See README and COPYING for more details.
 */

#include "includes.h"

#include "common.h"
#include "crypto/md5.h"
#include "crypto/sha1.h"
#include "tlsv1_common.h"
#include "tlsv1_record.h"


/**
 * tlsv1_record_set_cipher_suite - TLS record layer: Set cipher suite
 * @rl: Pointer to TLS record layer data
 * @cipher_suite: New cipher suite
 * Returns: 0 on success, -1 on failure
 *
 * This function is used to prepare TLS record layer for cipher suite change.
 * tlsv1_record_change_write_cipher() and
 * tlsv1_record_change_read_cipher() functions can then be used to change the
 * currently used ciphers.
 */
int tlsv1_record_set_cipher_suite(struct tlsv1_record_layer *rl,
        u16 cipher_suite)
{
    const struct tls_cipher_suite *suite;
    const struct tls_cipher_data *data;

    wpa_printf(MSG_DEBUG, "TLSv1: Selected cipher suite: 0x%04x",
            cipher_suite);
    rl->cipher_suite = cipher_suite;

    suite = tls_get_cipher_suite(cipher_suite);
    if (suite == NULL)
        return -1;

    if (suite->hash == TLS_HASH_MD5) {
        rl->hash_alg = CRYPTO_HASH_ALG_HMAC_MD5;
        rl->hash_size = MD5_MAC_LEN;
    } else if (suite->hash == TLS_HASH_SHA) {
        rl->hash_alg = CRYPTO_HASH_ALG_HMAC_SHA1;
        rl->hash_size = SHA1_MAC_LEN;
    }

    data = tls_get_cipher_data(suite->cipher);
    if (data == NULL)
        return -1;

    rl->key_material_len = data->key_material;
    rl->iv_size = data->block_size;
    rl->cipher_alg = data->alg;

    return 0;
}


/**
 * tlsv1_record_change_write_cipher - TLS record layer: Change write cipher
 * @rl: Pointer to TLS record layer data
 * Returns: 0 on success (cipher changed), -1 on failure
 *
 * This function changes TLS record layer to use the new cipher suite
 * configured with tlsv1_record_set_cipher_suite() for writing.
 */
int tlsv1_record_change_write_cipher(struct tlsv1_record_layer *rl)
{
    wpa_printf(MSG_DEBUG, "TLSv1: Record Layer - New write cipher suite "
            "0x%04x", rl->cipher_suite);
    rl->write_cipher_suite = rl->cipher_suite;
    os_memset(rl->write_seq_num, 0, TLS_SEQ_NUM_LEN);

    if (rl->write_cbc) {
        crypto_cipher_deinit(rl->write_cbc);
        rl->write_cbc = NULL;
    }
    if (rl->cipher_alg != CRYPTO_CIPHER_NULL) {
        rl->write_cbc = crypto_cipher_init(rl->cipher_alg,
                rl->write_iv, rl->write_key,
                rl->key_material_len);
        if (rl->write_cbc == NULL) {
            wpa_printf(MSG_DEBUG, "TLSv1: Failed to initialize "
                    "cipher");
            return -1;
        }
    }

    return 0;
}


/**
 * tlsv1_record_change_read_cipher - TLS record layer: Change read cipher
 * @rl: Pointer to TLS record layer data
 * Returns: 0 on success (cipher changed), -1 on failure
 *
 * This function changes TLS record layer to use the new cipher suite
 * configured with tlsv1_record_set_cipher_suite() for reading.
 */
int tlsv1_record_change_read_cipher(struct tlsv1_record_layer *rl)
{
    wpa_printf(MSG_DEBUG, "TLSv1: Record Layer - New read cipher suite "
            "0x%04x", rl->cipher_suite);
    rl->read_cipher_suite = rl->cipher_suite;
    os_memset(rl->read_seq_num, 0, TLS_SEQ_NUM_LEN);

    if (rl->read_cbc) {
        crypto_cipher_deinit(rl->read_cbc);
        rl->read_cbc = NULL;
    }
    if (rl->cipher_alg != CRYPTO_CIPHER_NULL) {
        rl->read_cbc = crypto_cipher_init(rl->cipher_alg,
                rl->read_iv, rl->read_key,
                rl->key_material_len);
        if (rl->read_cbc == NULL) {
            wpa_printf(MSG_DEBUG, "TLSv1: Failed to initialize "
                    "cipher");
            return -1;
        }
    }

    return 0;
}


/**
 * tlsv1_record_send - TLS record layer: Send a message
 * @rl: Pointer to TLS record layer data
 * @content_type: Content type (TLS_CONTENT_TYPE_*)
 * @buf: Buffer to send (with TLS_RECORD_HEADER_LEN octets reserved in the
 * beginning for record layer to fill in; payload filled in after this and
 * extra space in the end for HMAC).
 * @buf_size: Maximum buf size
 * @payload_len: Length of the payload
 * @out_len: Buffer for returning the used buf length
 * Returns: 0 on success, -1 on failure
 *
 * This function fills in the TLS record layer header, adds HMAC, and encrypts
 * the data using the current write cipher.
 */
int tlsv1_record_send(struct tlsv1_record_layer *rl, u8 content_type, u8 *buf,
        size_t buf_size, size_t payload_len, size_t *out_len)
{
    u8 *pos, *ct_start, *length, *payload;
    struct crypto_hash *hmac;
    size_t clen;

    pos = buf;
    /* ContentType type */
    ct_start = pos;
    *pos++ = content_type;
    /* ProtocolVersion version */
    WPA_PUT_BE16(pos, TLS_VERSION);
    pos += 2;
    /* uint16 length */
    length = pos;
    WPA_PUT_BE16(length, payload_len);
    pos += 2;

    /* opaque fragment[TLSPlaintext.length] */
    payload = pos;
    pos += payload_len;

    if (rl->write_cipher_suite != TLS_NULL_WITH_NULL_NULL) {
        hmac = crypto_hash_init(rl->hash_alg, rl->write_mac_secret,
                rl->hash_size);
        if (hmac == NULL) {
            wpa_printf(MSG_DEBUG, "TLSv1: Record Layer - Failed "
                    "to initialize HMAC");
            return -1;
        }
        crypto_hash_update(hmac, rl->write_seq_num, TLS_SEQ_NUM_LEN);
        /* type + version + length + fragment */
        crypto_hash_update(hmac, ct_start, pos - ct_start);
        clen = buf + buf_size - pos;
        if (clen < rl->hash_size) {
            wpa_printf(MSG_DEBUG, "TLSv1: Record Layer - Not "
                    "enough room for MAC");
            crypto_hash_finish(hmac, NULL, NULL);
            return -1;
        }

        if (crypto_hash_finish(hmac, pos, &clen) < 0) {
            wpa_printf(MSG_DEBUG, "TLSv1: Record Layer - Failed "
                    "to calculate HMAC");
            return -1;
        }
        wpa_hexdump(MSG_MSGDUMP, "TLSv1: Record Layer - Write HMAC",
                pos, clen);
        pos += clen;
        if (rl->iv_size) {
            size_t len = pos - payload;
            size_t pad;
            pad = (len + 1) % rl->iv_size;
            if (pad)
                pad = rl->iv_size - pad;
            if (pos + pad + 1 > buf + buf_size) {
                wpa_printf(MSG_DEBUG, "TLSv1: No room for "
                        "block cipher padding");
                return -1;
            }
            os_memset(pos, pad, pad + 1);
            pos += pad + 1;
        }

        if (crypto_cipher_encrypt(rl->write_cbc, payload,
                    payload, pos - payload) < 0)
            return -1;
    }

    WPA_PUT_BE16(length, pos - length - 2);
    inc_byte_array(rl->write_seq_num, TLS_SEQ_NUM_LEN);

    *out_len = pos - buf;

    return 0;
}


/**
 * tlsv1_record_receive - TLS record layer: Process a received message
 * @rl: Pointer to TLS record layer data
 * @in_data: Received data
 * @in_len: Length of the received data
 * @out_data: Buffer for output data (must be at least as long as in_data)
 * @out_len: Set to maximum out_data length by caller; used to return the
 * length of the used data
 * @alert: Buffer for returning an alert value on failure
 * Returns: 0 on success, -1 on failure
 *
 * This function decrypts the received message, verifies HMAC and TLS record
 * layer header.
 */
int tlsv1_record_receive(struct tlsv1_record_layer *rl,
        const u8 *in_data, size_t in_len,
        u8 *out_data, size_t *out_len, u8 *alert)
{
    size_t i, rlen, hlen;
    u8 padlen;
    struct crypto_hash *hmac;
    u8 len[2], hash[100];

    wpa_hexdump(MSG_MSGDUMP, "TLSv1: Record Layer - Received",
            in_data, in_len);

    if (in_len < TLS_RECORD_HEADER_LEN) {
        wpa_printf(MSG_DEBUG, "TLSv1: Too short record (in_len=%lu)",
                (unsigned long) in_len);
        *alert = TLS_ALERT_DECODE_ERROR;
        return -1;
    }

    wpa_printf(MSG_DEBUG, "TLSv1: Received content type %d version %d.%d "
            "length %d", in_data[0], in_data[1], in_data[2],
            WPA_GET_BE16(in_data + 3));

    if (in_data[0] != TLS_CONTENT_TYPE_HANDSHAKE &&
            in_data[0] != TLS_CONTENT_TYPE_CHANGE_CIPHER_SPEC &&
            in_data[0] != TLS_CONTENT_TYPE_ALERT &&
            in_data[0] != TLS_CONTENT_TYPE_APPLICATION_DATA) {
        wpa_printf(MSG_DEBUG, "TLSv1: Unexpected content type 0x%x",
                in_data[0]);
        *alert = TLS_ALERT_UNEXPECTED_MESSAGE;
        return -1;
    }

    if (WPA_GET_BE16(in_data + 1) != TLS_VERSION) {
        wpa_printf(MSG_DEBUG, "TLSv1: Unexpected protocol version "
                "%d.%d", in_data[1], in_data[2]);
        *alert = TLS_ALERT_PROTOCOL_VERSION;
        return -1;
    }

    rlen = WPA_GET_BE16(in_data + 3);

    /* TLSCiphertext must not be more than 2^14+2048 bytes */
    if (TLS_RECORD_HEADER_LEN + rlen > 18432) {
        wpa_printf(MSG_DEBUG, "TLSv1: Record overflow (len=%lu)",
                (unsigned long) (TLS_RECORD_HEADER_LEN + rlen));
        *alert = TLS_ALERT_RECORD_OVERFLOW;
        return -1;
    }

    in_data += TLS_RECORD_HEADER_LEN;
    in_len -= TLS_RECORD_HEADER_LEN;

    if (rlen > in_len) {
        wpa_printf(MSG_DEBUG, "TLSv1: Not all record data included "
                "(rlen=%lu > in_len=%lu)",
                (unsigned long) rlen, (unsigned long) in_len);
        *alert = TLS_ALERT_DECODE_ERROR;
        return -1;
    }

    in_len = rlen;

    if (*out_len < in_len) {
        wpa_printf(MSG_DEBUG, "TLSv1: Not enough output buffer for "
                "processing received record");
        *alert = TLS_ALERT_INTERNAL_ERROR;
        return -1;
    }

    os_memcpy(out_data, in_data, in_len);
    *out_len = in_len;

    if (rl->read_cipher_suite != TLS_NULL_WITH_NULL_NULL) {
        if (crypto_cipher_decrypt(rl->read_cbc, out_data,
                    out_data, in_len) < 0) {
            *alert = TLS_ALERT_DECRYPTION_FAILED;
            return -1;
        }
        if (rl->iv_size) {
            if (in_len == 0) {
                wpa_printf(MSG_DEBUG, "TLSv1: Too short record"
                        " (no pad)");
                *alert = TLS_ALERT_DECODE_ERROR;
                return -1;
            }
            padlen = out_data[in_len - 1];
            if (padlen >= in_len) {
                wpa_printf(MSG_DEBUG, "TLSv1: Incorrect pad "
                        "length (%u, in_len=%lu) in "
                        "received record",
                        padlen, (unsigned long) in_len);
                *alert = TLS_ALERT_DECRYPTION_FAILED;
                return -1;
            }
            for (i = in_len - padlen; i < in_len; i++) {
                if (out_data[i] != padlen) {
                    wpa_hexdump(MSG_DEBUG,
                            "TLSv1: Invalid pad in "
                            "received record",
                            out_data + in_len - padlen,
                            padlen);
                    *alert = TLS_ALERT_DECRYPTION_FAILED;
                    return -1;
                }
            }

            *out_len -= padlen + 1;
        }

        wpa_hexdump(MSG_MSGDUMP,
                "TLSv1: Record Layer - Decrypted data",
                out_data, in_len);

        if (*out_len < rl->hash_size) {
            wpa_printf(MSG_DEBUG, "TLSv1: Too short record; no "
                    "hash value");
            *alert = TLS_ALERT_INTERNAL_ERROR;
            return -1;
        }

        *out_len -= rl->hash_size;

        hmac = crypto_hash_init(rl->hash_alg, rl->read_mac_secret,
                rl->hash_size);
        if (hmac == NULL) {
            wpa_printf(MSG_DEBUG, "TLSv1: Record Layer - Failed "
                    "to initialize HMAC");
            *alert = TLS_ALERT_INTERNAL_ERROR;
            return -1;
        }

        crypto_hash_update(hmac, rl->read_seq_num, TLS_SEQ_NUM_LEN);
        /* type + version + length + fragment */
        crypto_hash_update(hmac, in_data - TLS_RECORD_HEADER_LEN, 3);
        WPA_PUT_BE16(len, *out_len);
        crypto_hash_update(hmac, len, 2);
        crypto_hash_update(hmac, out_data, *out_len);
        hlen = sizeof(hash);
        if (crypto_hash_finish(hmac, hash, &hlen) < 0) {
            wpa_printf(MSG_DEBUG, "TLSv1: Record Layer - Failed "
                    "to calculate HMAC");
            return -1;
        }
        if (hlen != rl->hash_size ||
                os_memcmp(hash, out_data + *out_len, hlen) != 0) {
            wpa_printf(MSG_DEBUG, "TLSv1: Invalid HMAC value in "
                    "received message");
            *alert = TLS_ALERT_BAD_RECORD_MAC;
            return -1;
        }
    }

    /* TLSCompressed must not be more than 2^14+1024 bytes */
    if (TLS_RECORD_HEADER_LEN + *out_len > 17408) {
        wpa_printf(MSG_DEBUG, "TLSv1: Record overflow (len=%lu)",
                (unsigned long) (TLS_RECORD_HEADER_LEN + *out_len));
        *alert = TLS_ALERT_RECORD_OVERFLOW;
        return -1;
    }

    inc_byte_array(rl->read_seq_num, TLS_SEQ_NUM_LEN);

    return 0;
}
